Telegraph transmitting system



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G. C. GUMMINGS TELEGRAPH TRANSMITTING SYSTEM Filed May l0, 1939 @sa n o o3 o /0/, O o Oo o l U- /163' A47@ E- ST9@ 4 gsm; :j I XML;

//\/ l/E/V TOR CUM/NGS Patented Dec. 10, 1940 UNITE. site Application May 10, 1939, Serial No. 272,759

v 9 Claims.

This invention relates to telegraph systems and particularly to a device for transmitting telegraph signals from a single telegraph transmitter to a large number of telegraph receivers 5 simultaneously. `Various devices for accomplishing this purpose are well known in the communication industry. The invention herein is an improved means for lperforming this'function.

m An object of this invention is improved transmission oi telegraph communication from a single transmitter to a plurality of receivers.

In the operation oi telegraph and teletypewriter systems it frequently becomes necessary to transmit communication signals to a large number of outlying points from a common sender as in the distribution of news, stock quotations, police alarms, etc., by means of wire networks or radio telegraph networks. In such if). cases it is desirable that a single transmitting source, or multiple sender as it is known in the art,` be used to serve as many connected lines as possible, without impairment of the transmitted signals beyond permissible limits and without '.35 overloading the common transmitting device beyond its operable current carrying capacity. It is obvious that as the number of lines with which the common sender is connected may be increased, in an operable system, the number of such senders required is reduced. In the testing of lines also, itis desirable for reasons of econ orny te make it possible to interconnect as many lines as possible to a common signaling source.

A feature of this invention is a singletele- :2.3 graph sending device controlling the grid potential of a plurality of high vacuum tubes.

A further feature of this invention is an arrangement wherein a plurality of high vacuum tubes arranged in' pairs are connected to the lo output of a transmitter distributor and one tube of each pair is used for transmitting marking signals and the other tube 4of each pair is used for transmitting spacing signals in a telegraph transmission circuit.

A further feature of this invention is a pair of high vacuum tubes having their output circuits connected to corresponding windings of a plurality of polar relays arranged in a parallel 50 group. Each of said relays has two windings, one in series with the output circuit of each of said pair of tubes.

These and other features will be made apparent in the detailed description and claims hereinunder.

(Ul. 17d-73) orties' circuit. The

conventional transmitter distributor, arranged to send a series of pulses of equal length, is indicated as the common transmitter of this gure. tive transmitter distributor Fig. 1A shows an alternaarrangement for that part of Fig. l above the line XX. In this ligure, a widely known tape controlled start-stop transmitter distributor arranged to send Baudot code signals is shown according to convention.

the usual In the drawing, biasing negative battery is normally connected between the grid and cathode of each tube and positive battery to the anode of each tube so ,that neither tube is conducting. The circuits for this condition may be traced as follows:

For tube |62 grid the circuit may be `traced from ground M8 to the positive pole of battery |2, through |48 to the positive negative pole, through resistance H6, junction point i555 and resistance Ill to the grid of tube For tube |633 grid, the circuit may be traced from ground Ille, to the positive pole of battery |2|, through said battery to the negative pole, through resistances ||8 and H9 to the grid of tube |93.

The output circuits for the tubes may be traced from ground i530, to the negative pole of battery |5I, through said battery to the positive pole and through resistance |28 to a parallel circuit.

cuit extends through the top winding of polar relay iilli to the anode of the tube m2.

second branch One branch of said parallel cir- The extends through the bottom winding of po-lar relay IM to the anode oftube The cathodes of `tubes |82 and |3 are connected in parallel through resistance |46 to ground it? The grids of tubes are each suiciently negative with respect to their cathodes, for this condition, so that neither one is conducting. sweeps across the rings of distributor The conducting brush ||52` IDI,

bridging the gap between solid conducting ring It and the successive conducting segments of ring |54 which are alternately marked M, for

mark, and S, for space. the gap between" solidconducting ring |63 and When brush |52 bridges the first conducting M segment on ring |64, a circuit may be traced from ground |41, through ring H53, brush |62 and the rst, or left-hand` segment M, tojunction point |65 in the biasing path for tube m2 `heretofore traced. This grounds biasing battery |20, at the right-hand terminal of resistance H6 and impresses ground potential, through resistance |65, to the grid of tube |02. This overcomes the biasing potential and tube |02 becomes conducting, permitting a current flow in its plate circuit heretofore traced through the top winding of relay |04, across the space between the anode and cathode of tube |02 and through resistance |45 to ground |61. The top winding of relay |04 is energized so that its armature is actuated to the right to engage its cooperating contact and transmit a marking signal over the loop connected to said armature to the distant receiving magnet ||0. The circuit for this may be traced from ground, through battery |22, the closed contact and armature of relay |04, the top conductor of the loop circuit to the distant station, through the winding of receiving magnet H0 and the bottom loop conductor back to ground at the central station.

`Resistance |34 and condenser |35, shunting the armature and contact of polar relay |03 are connected in the circuit to provide contact protection against sparking as the armature makes and breaks with its cooperating contact.

When the brush |62 leaves the rst conducting M or marking segment on ring |64, it sweeps across a small insulated gap between said M segment and the succeeding conducting S or spacing segment. During this interval ground is disconnected from the grid of tube |02 and tube |02 becomes non-conducting. When brush |62 engages the first S, or spacing segment, a circuit may be traced from ground |41, through ring |63, brush |62 and the iirst S segment, to junction point |66 in the biasing path heretofore traced to the grid of tube |03. This grounds biasing battery |2| at the right-hand terminal of resistance ||8 and impresses ground potential through resistance ||9 on the grid of tube |03. This overcomes the biasing potential and tube |03 becomes conducting, permitting a current to flow in its plate circuit, heretofore traced, through the bottom winding of relay |04, across the space between the anode and cathode of tube |03 and through resistance |46 to ground |01. The bottom Winding of relay |04 is energized. The effect of this is to disengage its armature from its contact. This opens the loop circuit heretofore traced, transmitting a spacing signal to the distant receiving magnet H0. When brush |02 has passed over the rst S segment of ring |64, ground is disconnected from the grid of tube |03 and the biasing battery l i8 again becomes effective to stop conduction through the plate circuit of tube |03. As brush |62 sweeps over the succeeding alternate M and S segments, the cycle is repeated. Assuming that relay |04 isproperly adjusted, unbiased marking and spacing signals are transmitted to the distant receiving magnets.

A number of circuits similar to the top loop circuit described are connected in multiple to the output of tubes |02 and |03. These circuits which are connected from plate batteries |53, |55, |51, |59 and |0I, extend through their respective resistances |20 to |33, and through the top and bottom windings of relays |05 to |00 to the anodes of tubes |02 and |03, respectively. These relays operate simultaneously with relay |04 to control their distant respective receiving magnets to ||5 connecting and disconnecting batteries |23 to |21 from the respective loops. Resistances |36 to- |40 and condensers |40 to |45 provide protection for their corresponding contacts.

Six relay circuits have been shown multipled to the output of the one pair of tubes |02 and |03. The number of circuits which may be so connected is dependent on the ratio of the output current of each tube to the operating current required for a winding. If, for instance, the output current of a tube is 60 milliamperes and each winding requires 10 milliamperes, the top windings of six relays may be connected in parallel to the output of one tube and the bottom windings of siX relays may be connected in parallel to the output of a second tube. In the drawing, one pair of tubes only, shown connected to the distributor |0I, is arranged with a complete output circuit. 'I'he one pair shown and their connections are intended to be illustrative of the manner in which a plurality of pairs of tubes and their o-utput circuits may be connected to a distributor. All of the grids of the marking signal tubes would be connected together and also all of the grids of the spacing signal tubes. The number which may be connected is dependent on the current which may be passed through a distributor satisfactorily Without excessive commutation trouble, and the current drawn by the grid circuit of each tube. In one type of distributor in general use at present it has been found satisfactory to pass a current of 60 milliamperes. If one milliampere is required by the grid circuits of the tubes, 60 pairs of tubes may be connected to one distributor and, for the conditions assumed, one distributor and 60 pairs of tubes will serve 360 receiving magnets. Attention is called to the arrangement of the polar relays in the output circuit, wherein not more than one winding is in series in any circuit. This is an advantage afforded by the present invention, as it is not necessary, with the arrangement described herein, to connect successive polar relays in series, with the attendant signal impairment, in order to obtain a satisfactory output from one transmitting device. However, it is possible, at the sacrice of some signal quality, to connect transmitting relay windings in series with the windings of relays |04 to |09 up to the limit of the allowable signal quality impairment.

The invention will be used in testing as a means of transmitting substantially perfect signals from a single transmitting source to a large number of telegraph receiving circuits. Its most important commercial use, however, will probably be as a telegraph message broadcasting de- 1 vice. When used in this capacity, alternate marking and spacing signals are not transmitted. Instead the message to be broadcast is rst recorded on a tape which is thereafter fed through n a well-known cam-controlled contacting device cooperating with the transmitting distributor in a well-known manner to overcome the bias on either tube |02 or |03 in accordance with the particular combination of a live-unit code corresponding to the character to be transmitted. With this arrangement, as shown in Fig. 1A, each of five successive segments of ring |64 is connected individually to an armature on the contacting device. Each armature cooperates between an individual pair of opposed contacts associated therewith. All of the contacts on the same side of said armatures are multipled together and connected to junction point |05. All of the contacts on the opposite side of said armatures are multipledtogether and connected to the junction point |66, The position of each armature is controlled in sequence in a wellknown manner by a cam, to engage one or the other of its cooperating contacts in accordance with the punchings in the` message tape. The solid ring |53 is grounded as i nthe drawing. As brush I sweeps over ring |53 and the segments of ring |4, ground is connected through each segment in succession to the junction point |65 or |66 in accordance with the code punched in the tape instead of alternately. In addition to the i'lve elements comprising the character, a start signal is transmitted by connecting ground through ring |63', brush |62 and a segment located immediately before the iirst of the five character segments directly to junction point |66 to transmit a space signal las a i start signal. Ground is also connected through ring |53', brush |52 and asegment located immediately after the segment for the last element of the character, directly to junction point |65 to transmit a marking signal at the end of each character as a stop signal. For the broadcasting of messages, essentially, the cam contacts and distributor cooperate to connect ground in accordance with the punched code characters to the grids of the marking or spacing tubes |52 or |03.

What is claimed is:

l. In a telegraph system, a single telegraph signal transmitter, a rst and a second high vacuurn discharge `device and a plurality of polar relays, a rst and a second input circuit connecting said iirst and second discharge devices to said transmitter, a rst and a second output circuit, each comprising a winding on each of said relays connecting said discharge devices to said relays, means for transmitting marking signals through said rst output circuit only, and means for transmitting spacing signals through said second output circuit only.

2. In a telegraph system, a transmitting distributor, a first circuit connecting said distributor to the input of a rst high vacuum discharge device, a second circuit connecting said distributor to the input of a second high vacuum discharge device, a first output circuit connecting said first device to a rst winding on a polar relay, and a second output circuit connecting said second device to a second winding on said relay.

3. In a direct current telegraph system, a single telegraph signal transmitter, a pair of high vacuum discharge tubes connected to said transmitter, a plurality of telegraph receiving channels connected to the outputs of said pair of tubes, and means for operating said receiving channels substantially in unison in response to the operation of said transmitter.

4. In a telegraph system, a telegraph signal transmitter, a plurality of vacuum tubes arranged in pairs connected to said transmitter, means in the circuits connecting each of said pairs of tubes to said transmitters for conditioning a first tube in each of said pairs to con- `duct marking signals only, and means in said circuits for conditioning the second tube in each of said pairs to conduct spacing signals only.

5. In a telegraph system, a plurality of polar relays, a rst and a second winding on each of said relays, means for connecting said first windings in parallel to the output of a first high vacuum discharge device, and means for connecting said second windings in parallel to the output of a second high vacuum discharge device.

6. In a telegraph system, a plurality of polar relays, individual groups of said plurality having individual relays of each group with corresponding windings arranged in parallel to form two series circuits through each of said groups, a plurality of pairs of high vacuum tubes, one pair of each plurality associated with each'of said groups, the output circuit of one of said tubes `of each pair connected to the first of said series circuits and the output circuit of the other of said tubes of each pair connected to the second of said series circuits.

'1. In a telegraph system, a single telegraph transmitter arranged to transmit code messages, a plurality of groups vof telegraph receiving channels and individual circuits each comprising a pair of high vacuum discharge tubes connecting each of said groups of said receiving channels to said transmitter.

8. In a telegraph system, a single telegraph transmitter, a plurality of telegraph receiving channels, an individual one-way telegraph circuit connecting said transmitter and said plurality of receiving channels comprising a pair of high vacuum discharge devices one of which devices responds to a marking signal and the other of which responds to a spacing signal transmitted by said transmitter.

9. In a direct current telegraph system, a broadcasting circuit comprising a single transmitter connected through a pair of high vacuum discharge devices to a plurality of telegraph receiving channels, means in said circuit, responsive to marking signal means in said transmitter, for energizing one of said tubes of said pair to transmit a marking signal to said plurality of channels simultaneously, `and means in said circuit responsive to spacing signal means in said transmitter for energizing the other of said tubes of said pair to transmit a spacing signal to said plurality of channels simultaneously.

GEORGE C. CUMMINGS. 

